1. Field of the Invention
The present invention relates generally to synthetic turf for landscaping, roofing, and athletic fields, and more particularly to synthetic turf having a cooling layer to substantially dissipate heat buildup common with synthetic turf. The invention also relates to
2. Description of the Related Art
Traditionally, athletic fields, as well as landscaped areas for homes and businesses, are covered with a natural grass covering. The natural grass is advantageous for cushioning and ability to quickly recover from abuse from weather, people, or both.
In recent years, however, many athletic fields have been converted from natural grass to synthetic turf systems. The reasons for converting to synthetic turf is most often linked to the high costs and time related to maintaining natural grass. Further, natural grass may have problems growing in certain environmental and man-made conditions, such as for example, desert regions, spaces shaded by buildings, domed fields and high traffic areas. In areas where the natural grass cannot grow properly or adequately, injuries can result from inadequate footing. In addition, poorly growing natural grass is typically not aesthetically pleasing.
Synthetic turf systems have improved over the years to appear more like natural grass coverings. Other improvements have been made to give more cushioning and elasticity to the synthetic turf to make it more equal to the advantages of natural grass turf.
However, a primary disadvantage of synthetic turf systems still exists. In particular, most synthetic turf systems are comprised primarily of plastics, such as, for example, polyolefin. Such plastics absorb, retain, and radiate heat that can increase the temperature on a field to a potentially fatal level. Even the American Academy of Pediatrics has identified infill artificial turf as contributing to elevating a person's core body temperature, thereby leading to heat related injuries such as, for example, heat cramps, heat exhaustion and heat stroke.
It has been found that naked synthetic turf systems, that is, synthetic tuft coverings without infill material, such as, for example, sand and rubber, can reach temperatures of 140° F. or greater. Natural grass coverings measure about 85° F. under similar circumstances. Essentially, the materials comprising most synthetic turf systems absorb heat from the sun and retain the heat in the ground to a much greater extent than natural grass coverings. Sand and rubber granules have been used as infill to increase footing and playability of athletic fields, but such infill materials do not mitigate heating issues of infill artificial tuft. In fact, rubber infill may actually contribute to increasing the temperature of the artificial turf. Lighter colored rubber granules and wetting the sand infill have been proposed as a mean by which to try and decrease the overall temperature of the synthetic turf system, however, such proposals tend to cool the artificial turf for a very limited, time and only at an almost insignificant temperature change.
In addition to being related to increasing heat-related injuries, synthetic turf systems also are associated with heat pollution. The massive amount of heat rising from urban areas is increasingly being linked to both a delay and stimulation of precipitation. Some areas are experiencing a noticeable decrease in much needed rain and snow, while other areas are seeing an increase. There is strong support that heat and pollution from urban areas effects climate in an alarming way; primarily by redistributing water in an undesired fashion.
As such, governments are considering and implementing environmental standards to limit the heat generated from urban areas. Some of the standards call for increased natural green spaces and fewer areas of blacktop and concrete, that is, artificial spaces that buildup and give off great amounts of heat pollution. Typical synthetic turf systems can behave very much like blacktop When it comes to heat pollution.
Attempts have been made to decrease the temperature of synthetic turf systems. Attempts to cool synthetic tuft coverings include watering down the coverings. However the water quickly evaporates. More recent attempts include mechanical means in which a series of cooling pipes are constructed under the synthetic turf systems. However, such mechanical means is expensive and would require removing currently laid synthetic turf systems.
Ceramic beads having about 50% porosity have been combined with sand and rubber granules to supplement mechanical cooling systems as a means for cooling artificial turf coverings. However, the ceramic beads are unable to hold enough water to significantly decrease the temperature of the synthetic turf system. Lighter colored rubber has also been proposed as a means for decreasing the temperature of the synthetic turf system, but also does not lend to significantly decreasing the overall temperature of the synthetic turf system.
Other means of cooling synthetic turfs are set forth in U.S. Pat. No. 5,153,553 to Tetrault where super absorbent polymers are included in infill. Although such means is successful in decreasing synthetic turf temperatures, the super absorbent polymers in such circumstances risk being separated from the associated synthetic turf due to weather and wear and tear.
Thus, what is needed is an economically affordable means for cooling synthetic turf systems over a significant period of time without concern of loss of cooling materials that are also environmentally friendly.